Pediatric RSV-Associated Hospitalizations Before and During the COVID-19 Pandemic

Abstract

ImportanceRespiratory syncytial virus (RSV) is a leading cause of pediatric hospitalizations.ObjectiveTo describe the epidemiology and burden of RSV-associated hospitalizations among children and adolescents in Canadian tertiary pediatric hospitals from 2017 to 2022, including changes during the COVID-19 pandemic.Design, Setting, and ParticipantsThis cross-sectional study was conducted during 5 RSV seasons (2017-2018 to 2021-2022) at 13 pediatric tertiary care centers from the Canadian Immunization Monitoring Program Active (IMPACT) program. Hospitalized children and adolescents aged 0 to 16 years with laboratory-confirmed RSV infection were included.Main Outcomes and MeasuresThe proportion of all-cause admissions associated with RSV and counts and proportions of RSV hospitalizations with intensive care unit (ICU) admission, prolonged stay (≥7 days), and in-hospital mortality were calculated overall and by season, age group, and region. Seasonality was described using epidemic curves. RSV hospitalizations for 2021-2022 were compared with those in the prepandemic period of 2017-2018 through 2019-2020. Bonferroni corrections were applied to P values to adjust for multiple statistical comparisons.ResultsAmong 11 014 RSV-associated hospitalizations in children and adolescents (6035 hospitalizations among male patients [54.8%]; 5488 hospitalizations among patients aged <6 months [49.8%]), 2594 hospitalizations (23.6%) had admission to the ICU, of which 1576 hospitalizations (60.8%) were among children aged less than 6 months. The median (IQR) hospital stay was 4 (2-6) days. The mean (SD) number of RSV-associated hospitalizations during prepandemic seasons was 2522 (88.8) hospitalizations. There were 58 hospitalizations reported in 2020-2021, followed by 3170 hospitalizations in 2021-2022. The proportion of all-cause hospitalizations associated with RSV increased from a mean of 3.2% (95% CI, 3.1%-3.3%) before the pandemic to 4.5% (95% CI, 4.3%-4.6%) in 2021-2022 (difference, 1.3 percentage points; 95% CI, 1.1-1.5 percentage points; corrected P < .001). A significant increase in RSV-associated hospitalizations was found in 2021-2022 for 3 provinces (difference range, 2.5 percentage points; 95% CI, 1.4-3.6 percentage points for Quebec to 2.9 percentage points; 95% CI, 1.4-3.5 percentage points for Alberta; all corrected P < .001). Age, sex, ICU admission, prolonged length of stay, and case fatality rate did not change in 2021-2022 compared with the prepandemic period. Interregional differences in RSV seasonality were accentuated in 2021-2022, with peaks for 1 province in October, 4 provinces in December, and 3 provinces in April, or May.Conclusions and RelevanceThis study found that the burden of RSV-associated hospitalizations in Canadian pediatric hospitals was substantial, particularly among infants aged less than 6 months, and RSV hospitalizations increased in 2021-2022 compared with the prepandemic period, while severity of illness remained similar. These findings suggest that RSV preventive strategies for infants aged less than 6 months would be associated with decreased RSV disease burden in children.

Hospital admissions for acute respiratory tract infections among infants from Nunavut and the burden of respiratory syncytial virus: a 10-year review in regional and tertiary hospitals

“…This may explain the larger proportion of RSV admissions with older infants in our study than previously reported. The IMPACT program at 13 Canadian tertiary pediatric hospitals reported 18.5% (1249 of 6737) of infant RSV hospitalizations were infants older than five months (20) versus 32.1% (108 of 336) in our study. The age of RSV admissions is an important factor in designing RSV prevention programs.…”

“…Previous studies concentrated on infant ARI admissions to tertiary care centers (8,20). Our findings highlight the importance of studying admissions to regional hospitals where the majority of hospitalizations occurred.…”

Cost-effectiveness of RSVpreF vaccine and nirsevimab for the prevention of respiratory syncytial virus disease in Canadian infants

“…A seasonal nirsevimab program with catch-up was more effective in reducing RSV burden than a year-round program as it ensures protection when infants require it most (i.e., during the RSV season) rather than providing protection outside the season. However, the effectiveness and cost-effectiveness of a seasonal program assumes that we know the start and end of the RSV season, which may be challenging, as demonstrated by disruptions in RSV seasonality associated with the COVID-19 pandemic (58, 59). The sensitivity of seasonal programs to timing of the RSV season underscores the importance of robust surveillance systems to determine optimal timing for implementing seasonal interventions.…”

Deviations in RSV epidemiological patterns and population structures in the United States following the COVID-19 pandemic

“…While fewer studies have been done in adult populations, they likewise have indicated higher RSV-A virulence as measured by clinical severity scores 47 . Following the resurgence of RSV post-2020, several multi-center studies observed increased infant hospitalization rates with unchanged clinical severity trends 48 , 49 , though no such contemporary studies have yet been reported in adults. Our data support the theory that worse clinical outcomes among hospitalized adults occur with RSV-A infection compared to RSV-B.…”